Urocitellus armatus (Kennicott, 1863)

Scientific Naming and Size

The Uinta ground squirrel, scientifically named Urocitellus armatus, is a moderately sized ground squirrel species. Adults measure 28 to 30 cm (11 to 12 in) in total length.

Weight Cycle

When they first emerge from hibernation, they weigh around 210 g (7.4 oz), and their weight increases steadily until they enter hibernation again in the fall.

Fur Coloration

Their fur ranges from brown to cinnamon in color, with a paler underside and grey fur on the sides of the head and neck.

Tail Characteristics

Their tails measure 6 to 8 cm (2.4 to 3.1 in), are buff-colored with a grey underside; this tail coloration differs from the ochraceous or reddish tails of closely related species like Belding's ground squirrel and Wyoming ground squirrel.

Female Anatomy

Female Uinta ground squirrels have ten teats.

Distribution

First described from specimens collected in the Uinta Mountains, this species is distributed in Wyoming west of the Green River, southwestern Montana, eastern Idaho, and northern and central Utah.

Habitat and Elevation

They live in open areas including meadows, pastures, and shrub-steppe habitats, at elevations between 1,220 and 2,440 m (4,000 and 8,010 ft).

Subspecies Status

No subspecies of Uinta ground squirrel are currently recognized.

Estrus Timing

Female Uinta ground squirrels enter estrus for just one afternoon each year, roughly two to four days after they emerge from hibernation.

Mating Behavior

Mating takes place underground, and each male may mate with multiple females.

Gestation and Litter

Gestation lasts 23 to 26 days, and produces an average litter of five young, which are born in early May.

Yearling Female Reproduction

Yearling females generally have fewer opportunities to mate because they emerge from their burrows later than older females, and they produce smaller litters than older females when they do mate.

Weaning and Burrow Emergence

Young Uinta ground squirrels are weaned at around 22 days old, and emerge from the burrow at approximately the same age.

Post-Weaning Parental Care

Despite still being small, weighing only around 60 g (2.1 oz), the mother almost completely abandons the young after weaning.

Juvenile Dispersal

The young disperse to establish their own territories over the following two to three weeks.

Lifespan

Uinta ground squirrels can live up to seven years in the wild.